I have an XL frame and I get my chain stuck in there too. The best advice I heard is when it gets jammed, just compress your suspension and it will work free without having to stop and get off the bike. That trick has saved me a couple of times, including in the first mile of a race where I would have been passed by the entire class if I had to stop.

In another thread Niner blamed it on improper setup/spacing, but I know I am using the proper spacing. It is just a flaw with the frame.